1. Field of the Invention
One disclosed aspect of the embodiments relates to a solid-state image pickup device, an image pickup system using the solid-state image pickup device, and a method of manufacturing the solid-state image pickup device.
2. Description of the Related Art
In an active-pixel type solid-state image pickup device represented by a Complementary Metal Oxide Semiconductor (CMOS) image sensor, it is proposed to a device having a global electronic shutter function or including focus detection pixels.
The global electronic shutter function is a function of starting and ending accumulation of photo-carriers (photo-charges) in a plurality of pixels, which are arrayed in a matrix pattern, simultaneously for all the pixels. The solid-state image pickup device having the global electronic shutter function includes, in each pixel, a photoelectric conversion portion and a carrier holding portion configured to hold carriers, which are generated by photoelectric conversion, for a certain time. The carrier holding portion in the solid-state image pickup device having the global electronic shutter function holds the carriers for a period from the end of the accumulation of the photo-carriers to read of the accumulated photo-carriers. There is a possibility that if, during such a period, carriers generated other than the photoelectric conversion portion are mixed into the carrier holding portion, the mixed carriers may generate a noise signal, thus causing degradation of image quality. Japanese Patent Laid-Open No. 2008-004692 discloses a structure where each pixel includes a photoelectric conversion portion and a carrier holding portion, and a light shielding film is disposed on the carrier holding portion.
Japanese Patent Laid-Open No. 2009-105358 discloses a solid-state image pickup device including focus detection pixels, in which a light shielding film having a slit is disposed in the focus detection pixel. Japanese Patent Laid-Open No. 2008-004692 mentions the light shielding film, but detailed discussion is not made regarding the light shielding film. Depending on the arrangement of the light shielding film, oblique light may become apt to enter the carrier holding portion, and carriers generated by the oblique light may be mixed into the carriers held in the carrier holding portion.
The solid-state image pickup device disclosed in Japanese Patent Laid-Open No. 2009-105358 also accompanies with a similar problem to that described above because detailed discussion is not made regarding the light shielding film including the slit.